The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
A hybrid electric vehicle may use both an internal combustion engine and an electric motor to provide torque for transmission in order to maximize fuel economy. To start an engine of a hybrid vehicle, a motor generator may function as an electric motor and draw electrical energy from a battery pack to drive the engine crankshaft. When the engine is running, the motor generator may function as a generator and be driven by the engine to recharge the battery pack.
In conventional hybrid vehicles, vehicle accessories, including but not limited to, air conditioning compressors, power steering pumps, water pumps, and secondary air pumps, are commonly powered by the engine. For example, the battery pack for the motor generator may lack the capacity to propel the vehicle and drive the vehicle accessories at the same time. This is especially true for mild hybrid vehicles. Generally, the motor generator of a mild hybrid vehicle may have very limited ability to propel a vehicle independently. To ensure proper operation of the vehicle accessories when the engine is off, multiple drive motors may be incorporated for driving the vehicle accessories. The multiple drive motors, however, take up space in the vehicles and add cost and weight.